The utilization of renewable energy has been highlighted to reduce greenhouse gas (carbon dioxide gas) emission. For example, JP 2008-131841 A has disclosed a technique for using the renewable energy in an electric vehicle (EV). Specifically, Patent Document 1 discloses a renewable energy using system including a renewable energy generation unit for generating power by using the renewable energy and a mobile body charging unit for charging a secondary battery of the mobile body, which moves by taking out electric energy from the secondary battery, by using the electric energy generated by the power generation according to the renewable energy generation unit. Also, for example, JP 2006-074868 A discloses a battery charging system of an electric vehicle including a communication unit which can transmit charging information of a battery mounted on the electric vehicle to outside. The battery charging system of the electric vehicle includes a service system which collectively manages battery information of individual users previously registered and sets a charging schedule based on present battery information transmitted from each vehicle and the previously accumulated battery information and a non-contact charging power supply system which is communicably connected to the service system and supplies the power to charge the battery without contacting with the vehicle according to an instruction from the service system.
Also, JP 2001-184406 A discloses a power supply system in which a customer can select the power generated by the green energy. The invention regarding the power supply system includes a notification control unit which notifies a power user of a kind of a power generation and its selling price by using a communication line, a power distribution control unit which receives a reservation instruction of the kind of the power source, its amount of consumption, or date to use the power transmitted from the power users via the communication line and instructs each power generating facility for each power source to supply the power by the amount of power consumption via the communication line, a use result database which records the kind of the power source and the amount of the power consumption for each power user, and a billing work control unit which calculates a power usage charge based on the kind of the power source, the amount of the power consumption, and the price for a certain period of time recorded in the use result database for each power user and charges to the power customer.